1058 General Notes. 
cally upon the relation of the appearance and duration of the 
tious forms of life upon the earth to the breaks in the coni 
the sedimentary rocks. Postulating an earth-wave which 
gradually force southward the depression of the Medit 
and thus convert Africa slowly into Europe, he endeavors 
what forms of life would be likely to persist. He then 
some of the appearances and extinctions occurring in the var 
formations, and concludes that the sequence of life upon thee 
points to the persistence of oceanic and continental areas, 
earth-movements of the nature of waves. The greatest 
in the series of strata in England are those between 
and lower old red sandstone, and between the Coal Measures 
the Permian. Beh: 
j MINERALOGY.’ 
THE INFLUENCE OF Ligut on Minerats.—It may not beg 
erally known that many minerals lose their color or fade whi 
the air. Experimes 
made by Erdmann, by placing fragments in sealed tubes and 
posing them to light for a year, led to the conclusion that air 
moisture had no ipfluence, but that light alone effected the 
in color, 
RUTILE IN Putocorrre.—The beautiful phenomenon 
ism is probably better shown in the well-known pale 
Burgess, Ontario county, Canada (often known as sta 
pi a ae other substance. The flame of a a 
through a e of the mica, a rs as a six or V 
As is shown by the niicioneone: this is due to the 
minute linear crystals which cross each other at angle 
The cause is the same as that which produces a two Or 5 
igure a street lamp is looked at ona rainy night th 
mbrella. 
Mineralogists have long been puzzled to know p 
these minute enclosed crystals are which thus proun. 
i ny and they will be interested to know that they 
rutile, r 
The needles are flattened and almost colorless in 
mica, but in a mica from Bodenmais, Sandberger has 
of a deep reddish-brown color. Williams has also feet 
needles of rutile in a magnesian mica which occurs l 
diorite from the Black Forest. ba 
Edited by Professor H. Carvitt, Lewis, Academy of n u 
detphia, to whom communications, papers for review, cte., 
u 
